1. Field of the Invention
This invention relates to an aeration tine device for aerating turf and soil and, more particularly, to an aeration tine device with a side-ejecting opening suitable for aerating turf of a wide lawn surface such as golf courses.
2. Description of Related Art
Turf aeration is to open channels in the soil for air and water movement and gas exchange in the root zone, and traditional turf aeration involves the process of punching holes in the soil and removing a portion of the soil and thatch layer via a coring or spooning action. To improve soil aeration, turf aeration tine devices are used for extracting plugs of turf, thatch and soil. There are two basic types of aerators: solid tine, hollow tine or core. Solid tine aeration is often called spiking and involves making a hole in the sod by pushing turf and sub-surface thatch and into the root zone. Although this type of aeration is beneficial, it does not bring cores to the surface, which slows the breakdown of thatch. Hollow tine aeration speeds up the decomposition of thatch by bringing soil and thatch to the surface where air, water and microbes vigorously break down thatch.
In hollow tine aeration, the aeration tines commonly have a generally tubular shape with a tapered hollow point designed so that a portion of turf and soil enters into the tip of the tine and is ejected through the other end or a side opening of the tine. Such tines are spiked downward as the tapered point of the aeration tine device is punched toward the turf surface with prescribed force by a turf aerator generally having wheels to move the working site. The turf aerator generally has plural tine arms for detachably attaching a number of tines, and during operation, each tine arm moves up and down reciprocally to spike the turf surface.
Numerous types of turf aeration apparatus have been developed to accomplish the process of core cultivation. Tine devices of hollow type can be found in, e.g., U.S. Pat. Nos. 4,924,944 and 5,495,895. In U.S. Pat. No. 4,924,944, a pair of tube shaped tine members and a center bar member are coupled at each generally rectangular upper end portion of the tine member to form a side ejecting double coring tine device. Each tine member has a circular lower end having an opening in communication with a side opening provided at a center stem to facilitate penetration into the turf. In U.S. Pat. No. 5,495,895, a tine device is illustrated as having a circular edge formed by thinning the forefront portion of a pipe material and having a head portion having a slightly larger diameter at the base end. The tine device is formed with an elongated hole for driving out of soil. The upper and lower end portions of the elongated hole are obliquely cut off to form sloped surfaces. The tine devices are of the form of a sharpened slightly tapered hollow metal tube, which may be vertically inserted and withdrawn from grass turf so as to extract a core.
Repetitive insertions of the tine device into the turf bring continual wearing on the tine metal member due to friction against the turf. Such wearing changes the length and the diameter of the tube member, and the operator has to replace the worn tine with a new tine to keep the coring operation in an accurate manner. One of the conventional efforts to solve such a problem is to provide a hard wearing resistant ring element that is fixed to the lower end of the tine. U.S. Pat. No. 3,586,109, describes a tubelike tine for being driven endwise into the turf, especially the turf of golf greens, which is characterized by the provision of an extremely hard wear-resistant element fixed to the working end of the tine.
The tine device described in U.S. Pat. No. 3,586,109, however, raises some problems when doing aeration to soil and turf. Sand and soil may easily stuff up the tubelike tine having an opening at a lower end of thereof, and if stuffed up once, the tine hardly recovers from the stuffed state because the tine repeatedly spikes the surface of soil and turf and because such a repeating action makes harder the stuffed soil placed in the interior of the tine. The tine also causes more friction at the lightly protruded surface of the hard tip provided at the lower end of the tine. Since the tine is moved reciprocally up and down as to spike the surface of turf and soil, the protruded hard tip portion is subject to higher friction when the tine is moved up and down reciprocally. This friction makes uneasy the soil aeration work in use of the tine of this type and may resultantly break down the tine as to separate the hard tip from the tine body portion as a worse situation. To prevent such a hard tip portion from separating, a possible solution is to increase the area adhering between the hard tip portion and the tine body portion. Fabrication of the tapered portion of the tine body portion as to render the contact area wider, however, brings higher costs, and since the tapered surface comes closely to extend parallel to the axial direction, spiking force may not be adequately transmitted to the hard tip from the tine body portion where the tapered face of the hard tip and the tapered end of the tine body portion face obliquely with respect to the axial direction of the tine.